scholarly journals Mermin's inequalities of multiple qubits with orthogonal measurements on IBM Q 53‐qubit system

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wei‐Jia Huang ◽  
Wei‐Chen Chien ◽  
Chien‐Hung Cho ◽  
Che‐Chun Huang ◽  
Tsung‐Wei Huang ◽  
...  
Keyword(s):  
Qubit System ◽  
Q 53

Passive and active nonlocality sharing for a two-qubit system via weak measurements

2019 ◽  
Vol 100 (5) ◽  
Author(s):  
Changliang Ren ◽  
Tianfeng Feng ◽  
Dan Yao ◽  
Haofei Shi ◽  
Jingling Chen ◽  
...  
Keyword(s):  
Weak Measurements ◽  
Qubit System

scholarly journals Local Information as an Essential Factor for Quantum Entanglement

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 728
Author(s):  
Zhaofeng Su
Keyword(s):  
Quantum Entanglement ◽  
Quantum Information Processing ◽  
Local Information ◽  
Essential Factor ◽  
Qubit System ◽  
Local Vectors ◽  
Correlation Parameters ◽  
The One ◽  
Local Parameters

Quantum entanglement is not only a fundamental concept in quantum mechanics but also a special resource for many important quantum information processing tasks. An intuitive way to understand quantum entanglement is to analyze its geometric parameters which include local parameters and correlation parameters. The correlation parameters have been extensively studied while the role of local parameters have not been drawn attention. In this paper, we investigate the question how local parameters of a two-qubit system affect quantum entanglement in both quantitative and qualitative perspective. Firstly, we find that the concurrence, a measure of quantum entanglement, of a general two-qubit state is bounded by the norms of local vectors and correlations matrix. Then, we derive a sufficient condition for a two-qubit being separable in perspective of local parameters. Finally, we find that different local parameters could make a state with fixed correlation matrix separable, entangled or even more qualitatively entangled than the one with vanished local parameters.

Entanglement classification of relaxed Greenberger-Horne-Zeilinger-symmetric states

2014 ◽  
Vol 14 (11&12) ◽  
pp. 937-948
Author(s):  
Eylee Jung ◽  
DaeKil Park
Keyword(s):  
Separable States ◽  
Qubit System ◽  
Symmetric States

In this paper we analyze entanglement classification of relaxed Greenberger-Horne-Zeilinger-symmetric states $\rho^{ES}$, which is parametrized by four real parameters $x$, $y_1$, $y_2$ and $y_3$. The condition for separable states of $\rho^{ES}$ is analytically derived. The higher classes such as bi-separable, W, and Greenberger-Horne-Zeilinger classes are roughly classified by making use of the class-specific optimal witnesses or map from the relaxed Greenberger-Horne-Zeilinger symmetry to the Greenberger-Horne-Zeilinger symmetry. From this analysis we guess that the entanglement classes of $\rho^{ES}$ are not dependent on $y_j \hspace{.2cm} (j=1,2,3)$ individually, but dependent on $y_1 + y_2 + y_3$ collectively. The difficulty arising in extension of analysis with Greenberger-Horne-Zeilinger symmetry to the higher-qubit system is discussed.

CONTROLLED TELEPORTATION OF ELECTRON SPIN STATE IN QUANTUM DOT VIA SINGLE PHOTON

2008 ◽  
Vol 06 (03) ◽  
pp. 553-560
Author(s):  
YAN-WEI WANG ◽  
MING-FENG WANG ◽  
YI-ZHUANG ZHENG
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Electron Spin ◽  
Spin State ◽  
Faraday Rotation ◽  
Quantum Teleportation ◽  
Single Photon ◽  
Controlled Teleportation ◽  
Controlled Quantum Teleportation ◽  
Qubit System

A controlled quantum teleportation scheme of electron spin state in a quantum dot is proposed. With the entanglement generating through the interaction between the quantum dots in microcavities and a single photon, the controlled teleportation can be implemented using Faraday rotation and single photon measurements. The scheme can be easily generalized to multi-qubit system.

scholarly journals Zero-knowledge convincing protocol on quantum bit is impossible

Quantum ◽  
2017 ◽  
Vol 1 ◽  
pp. 41 ◽  
Author(s):  
Pawel Horodecki ◽  
Michal Horodecki ◽  
Ryszard Horodecki
Keyword(s):  
Information Processing ◽  
Quantum State ◽  
Qubit State ◽  
Third Party ◽  
Zero Knowledge ◽  
Quantum Bit ◽  
Qubit System ◽  
Nonzero Probability

Consider two parties: Alice and Bob and suppose that Bob is given a qubit system in a quantum state ϕ, unknown to him. Alice knows ϕ and she is supposed to convince Bob that she knows ϕ sending some test message. Is it possible for her to convince Bob providing him "zero knowledge" i. e. no information about ϕ he has? We prove that there is no "zero knowledge" protocol of that kind. In fact it turns out that basing on Alice message, Bob (or third party - Eve - who can intercept the message) can synthetize a copy of the unknown qubit state ϕ with nonzero probability. This "no-go" result puts general constrains on information processing where information about quantum state is involved.

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